Concrete pump



April 14. 1970 A N. o. z uRlcH CONCRETE PUMP 2 Sheets-Sheet 1 Filed May 2l 1968` JNVENTOR. /V/K/a Q 'Zoe/cw y A TeA/E N. O. ZURICH CONCRETE PUMP April 14, 1970 2 Sheets-Sheet 2 Filed May 2l, 1968 Hlllllllllllll lum .lll

ATTORNEYS United States Patent O 3,506,382 CONCRETE PUMP Nikola O. Zurich, Milwaukee, Wis., assignor to Zurcon Corporation, Milwaukee, Wis., a corporation of Wiscousin Filed May 21, 1968, Ser. No. 730,794 Int. Cl. F0411 19/22, 21/02; F1611 25/12 U.S. Cl. 417--519 8 Claims ABSTRACT OF THE DISCLOSURE A piston type cement pump is operated by means of a screw having a coarse thread. Means are provided for lubricating the screw without disassembly and for water flushing either the piston alone or the passage for the concrete. An oscillating gate valve in the concrete passage operates in timed relation to the movement of the piston through a lost motion connection.

BACKGROUND OF THE INVENTION In the past, concrete pumps have been operated pri- Imarily by hydraulic mechanism which requires a source of hydraulic pressure, valves, and fittings having very close tolerances. Moreover, the cleaning of such devices is difficult and failure of the seals through wear can result in oil contaminating the concrete. My device uses a very much simplified mechanical drive which is completely isolated from the concrete and cannot result in oil contamination thereof, provides great reduction in speed with high power, isolation of the -drive from contamination by concrete, insensitivity to wear, new and efficient methods of water flushing the passages to clean out the concrete, and provides a new valve structure which is both insensitive to wear and is extremely positive in its timing and operation.

THE INVENTION The invention consists of a hopper for concrete which feeds a passage through which the concrete is to be pumped. A `single oscillating arcuate valve is provided which can close either the lower end of lthe hopper or the outlet passage, depending upon its position. The concrete is pumped by a piston adjacent the valve chamber, the piston being connected to the valve by means of a crank arm and ya lost motion link which pushes the valve to a position closing the outlet passage as the piston reaches the end of its pumping stroke and which returns the valve to a position closing the bottom of the hopper at the end of the retracting stroke during which concrete is being drawn into the cylinder. The piston is provided with trunnions, each of which carries a link containing a lost motion connection, so that the link is eiiective only at the respective ends of the stroke of the piston. The other end of each link is connected to a crank arm on the arcuate valve so that the valve is moved 90 alternately to a conduit closing position and a hopper closing position at the respective ends of the piston stroke. Also extending from the sides of the piston at the rear end are water fittings which supply water to a chamber within the piston which is provided with a check valve at the working face of the piston. When water is supplied through one of the fitting, with the other being closed, water passes through the check valve and the face of the piston to the valve chamber and thereafter through the concrete outlet conduit to clean them of concrete residues. When the second water fitting is left open, the water merely circulates within the piston and then leaves it through the second fitting, cleaning and cooling the interior. One of the trunnions also contains an oil fitting which leads to a passage to the center of the rear head of the piston and intersecting ICC the screw-threaded bore which receives the driving screw for the piston, thus permitting lubrication of the screw at any time. An inner wall member -in the piston isolates the chamber within which the screw operates from the chamber within which the water circulates.

The cylinder within which the piston operates is slotted to permit reciprocation of the trunnions and the water fittings, thus helping to guide the piston and prevent it from rotating with the screw, and serving as stops. A rear head on the cylinder contains the bearing for the screw, and the shaft of the screw extends through it to a reversible drive of any conventional type. Packing rings, preferably neoprene, are used in a groove in the piston adjacent the working face thereof. A specific embodiment is described herein but changes may be made within the scope of the claims without -departing from my invention. In particular, multiple pistons may be used.

DRAWINGS FIG. 1 is a vertical axial cross-sectional view of my device.

FIG. 2 is a cross-sectional view on line 2 2 of FIG. l.

F IG. 3 is a cross-sectional view on line 3 3 of FIG. 1.

FIG. 4 is a side view.

DESCRIPTION My device consists generally of a cylinder 10 within which is a piston 20. A hopper 30 opens at the bottom into a valve chamber 40 and an outlet conduit 42 receives concrete from the valve chamber and conducts it to its destination. Cylinder 10 also opens into valve chamber 40, and piston 20 operates within cylinder 10 to a point lat which its face is substantially flush with the connection with the valve chamber.

Cylinder 10 has a rear head 11 which is secured to the cylinder by any conventional means and which is provided with a bearing 12 which may desirably be a thrust bearing. The shaft of drive screw 13 extends through bearing 12 and head 11 and is connected to a reversing drive including gears 14, 14a which are driven by a conventional mechanism which drives gear 14 a fixed number of rotations in one direction and then the same number of rotations in the opposite direction. Cylinder 10 is slotted at 15, 15a, 15b and 15C to receive water connections and trunnion-s extending radially from piston 20 (which will be described), and to serve yas guides and stops for piston 20.

The piston 20 consists of a front head 21, a rear head 22, an outer cylindrical wall 23, an inner wall 24, and packings 25, preferably of neoprene, in a conventional groove near the forward end of piston 20. A threaded bore 26 in rear head 22 of piston 20 receives screw 13, so that in effect rear head 22 is a nut on screw '13. The pair of trunnions, 27, 270, extend from opposite sides of rear hea-d 22 through slots 15e and 15b of the cylinder 10. A grease fitting 27a is provided upon trunnion 27, communicating by means of a passage 27b with the threaded bore 26 which receives screw 13, for lubrication of the screw. A pair of couplings, which may take the form of capped pipe nipples, here design-ated as 28a and 28b, extend through slots 15 and 15a in cylinder 10, preferably at right angles to trunnions 27, 270, as shown. These nipples communicate with passage 28e extending into the space 24a between inner wall 24 and outer wall 23 of piston 20. A conventional check valve generally designated as 29 permits water to pass through head 21 whenever the bias of the check valve toward a closed position in head 21 is overcome by water pressure.

The valve chamber 40 is open to concrete hopper 30 and is also open to outlet duct 42, except as said openings are controlled by valve 41, which consists of an arcuate closure member 43 which is adapted to swing across the opening either to hopper 30 or to outlet duct 42 as will be described. Attached to closure 43 at each end is a sector 44 secured to a shaft 45 journaled in the side plates 46 of chamber 40. A pair of cranks 47 are respectively secured to each shaft 45 outside chamber 40, whereby valve member 41 may be moved from one of its two positions to the other. A pair of links generally designated as 48 are pivotally connected at 49 to respective cranks 47. In addition to the conventional fittings for pivotally connecting each link 48 to a crank pin 49, the link 48 is provided with an elongated slot 50 embracing a trunnion 27, or 270, and pivotally connecting links 48 in lost motion connection to trunnions 27, 270 on piston 20.

Theends of each slot 50` are so located with respect to cranks 47 and trunnions 27, 270 that at each end of each stroke of piston 20 a trunnion 27, 270 comes to the end of slot 50 and thereupon exerts a force on cranks 47 to turn the arcuate closure member 43 of valve 41 to a new position. As shown in FIG. 1, piston 20 has just arrived at the forward end of its stroke and trunnions 27, 270 have come to the forward end of slot 50 and have urged link 48 toward concrete outlet 42, displacing cranks 47 forwardly so that the arcuate member 43 now closes outlet 42. As the screw 13 is reversed, piston 20 will move backwardly in cylinder 10, drawing in concrete from hopper 30, until piston 20 reaches a point near the rearward end of its stroke, when trunnions 27, 270, will strike the rearward end of slot 50 and will urge links 48 rearwardly, rotating shafts 45 and oscillating closure member 43 90 to close the connection between hopper 30 and valve chamber 40. When the screw 13 is again reversed, initiating the forward stroke of piston 20 in cylinder 10, the concrete is driven out of outlet 42 4because closure member 43 prevents it from being driven back into hopper 30.

The neoprene seals 25 do an effective job of preventing concrete from entering cylinder 10, but my union is relatively insensitive to wear because cylinder is not required to seal hydraulic fluid for driving piston 20. Rather, the vscrew 13 operates in its own separate chamber 24b having inner wall 24 sealed to heads 21 and 22 thus sealing the screw and its lubrication away from the concrete and eliminating the necessity for the complexities of a hydraulic system.

If cooling is required the caps on nipples 28a and 28b may be removed and a water hose may be connected to one of them (or to both if the drain is not nearby). For flushing the system to dispose of concrete at the end of a period of use only one of the caps is removed from, for instance,.nipple 28a and water lls the space between inner wall 24 and outer wall 23 through a passage 28C. The water is forced out of check valve 29 and flushes chamber 40 and outlet passage 42 as well as cleaning valve 41. If desired, piston may be operated during this process in order to clean the walls of cylinder 10 as well.

It will be seen that my device is uniquely simple and effective in coping with the extreme wear problems caused by the pumping of concrete and the need of avoiding contamination of the concrete with hydraulic fluid. The latter is extremely likely in hydraulically driven mechanisms because the wear from the concrete soon causes leakage. More than one cylinder may be used in a single device.

I claim:

1. In a concrete pump, a valve chamber having an inlet and an outlet, a valve member in the chamber movable from an inlet closing to an outlet closing position, a cylinder communicating with the valve chamber, a piston oscillatable in the cylinder, and means connecting said piston to said valve member and adapted to move said valve member to an inlet closing position when said piston is farthest from said chamber and to an outlet closing position when said piston is nearest said chamber, the piston having spaced inner and outer walls, and front and rear heads respectively sealed to the inner and outer walls, the rear head being provided with means receiving a driving member for the piston within the area sealed to said inner wall.

2. The device of claim 1 in which said means includes a crank secured to said valve member and a lost motion link having respective ends pivoted to the crank and the piston.

3. In a concrete pump, a valve chamber having an inlet and an outlet, a valve member in the chamber movable from an inlet closing to an outlet closing position, a cylinder communicating with the valve chamber, a piston oscillatable in the cylinder, means to operate said valve synchronously with the piston, and drive means for the piston comprising a drive screw aligned with the piston, a threaded bore in the piston engaged with the screw, and means to rotate the screw alternately in each direction of rotation, the piston having spaced inner and outer walls, and front and rear heads respectively sealed to the inner and outer walls, the rear head being provided with said threaded bore within the area sealed to said inner wall.

4. The device of claim 3 in which said means to operate said valve includes slots in said cylinder, trunnions extending radially from said rear heads through said slots, links having elongated slots engaged with said trunnions, and a crank secured to said valve and pivotally secured to said link, Iwhereby to shift said valve only at the end of each stroke of the piston.

5. The device of claim 3 comprising a fitting on said piston for supplying water to the space between the inner and outer walls.

6. The device of claim 5 in which said cylinder is provided with a slot and said fitting extends radially through the slot.

7. The device of claim 6 in which said front head includes a check valve communicating between the space between said walls and the valve chamber and biased to open only when pressure in the space between said walls exceeds pressure in the valve chamber.

8. The device of claim 4 in which a said trunnion has a grease fitting and said rear head has a passage from said grease fitting to said threaded bore.

References Cited UNITED STATES PATENTS 608,361 8/1898 Craig 103-153 670,868 3/1901 Bode 103-153 1,316,558 9/1919 Cannon 103-153 1,933,722 11/1933 Farrar 74-57 2,017,975 10/1935 Kooyman 103-153 XR 2,062,200 11/1936 Ball 1013-228 XR 2,384,783 9/ 1945 Longenecker 103--228 3,266,435 8/1966 Smith 103--153 XR HENRY F. RADUAZO, Primary Examiner U.S. Cl. X.R. 

